1. Field of the Invention
The present invention concerns a press section of a paper machine.
2. Discussion of the Related Art
DE 40 25 021 A1 discloses a paper machine press section for dewatering a paper web, characterized by two mutually independent, endless and elastic press elements incapable of water absorption and passing the paper web, which with one of its sides alternately makes contact, through one or several press gaps in order to thereby ensure maximally equal properties on both sides of the paper web.
In other prior types of paper machines which instead of this water- and air-impermeable belt employ a wire, the edge strips of the paper web are cut off (for instance by water jets) from the web on the wire, so as to limit the web width. These edge strips can then be separated from the web as it is picked up from the wire by an edge suction pickup. The edge strips then travel on with the wire and, thus, can subsequently be run from the wire into the couch pit. In this context, reference is made to U.S. Pat. No. 5,256,257. Pick-up devices themselves have been described, e.g., in G 89 14 679. Concerned here is a pick-up scraper supported by blowing air in the pick-up operation.
This and similar prior methods for separating web and edge strips, however, cannot be used with the type of belt described above. While the transfer illustrated in the U.S. Pat. No. 4,943,351 shows a paper web transfer from a smooth and water-impermeable belt, what's illustrated here, though, is the transfer of the entire paper web to the drying section, and not the pickup of an edge strip into the couch pit, which proceeds under different conditions.
The problem underlying the present invention is to provide a device which enables the pickup of the edge strips from a water- and air-impermeable belt independently from the paper web.